fix equality issues due to Julia's recent hashing changes
fix equality issues due to Julia's recent hashing changes

tkelman/OpenCL.jl,JuliaPackageMirrors/OpenCL.jl,JuliaPackageMirrors/OpenCL.jl,tkelman/OpenCL.jl,yuyichao/OpenCL.jl,yuyichao/OpenCL.jl